1. Field of the Invention
This invention relates to ether and alcohol solutions of nitrocellulose useful in forming flexible cellulose film bandages which adhere to human skin, and more particularly to an improved method of preparing such solutions.
2. Prior Art
Alcohol and ether solutions of nitrocellulose, known generically as collodion, have been used for many years to form flexible film coverings which adhere directly to the skin to protect cuts, abrasions and the like. Various additives such as castor oil which slows the rate of evaporation of the solution and increases its adhesion to the skin, and acetone and other volatile solvents and plasticizers may be formulated with the solution to provide a material which is easy to apply to the skin and dries within a few seconds to form a smooth, flexible, highly tenacious coating. These coating solutions are termed court plaster.
The cellulose fibers must of course be homogeneously dispersed through the resulting solution. Because of the structure of the cellulose fibers and viscosity of the solution, it is difficult to obtain this dispersion and the material must be prepared on a batch basis and mixed for long periods of time. The long mixing time is required so that the solvents will have sufficient time to act upon the cellulose fibers to break them up and to cause the cellulose to be thoroughly dispersed within the solution. It was previously common for these solutions to be mixed for several days in order to obtain a smooth homogeneous solution.